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MARINE ENVIRONMENTS: Marine environments are classified into three broad categories: Estuaries: semi-enclosed coastal water bodies that have a free connection to the open ocean, where seawater enters and mixes with freshwater derived from land drainage with high productivity. Coastal waters: Overlie the inner continental shelf, typically within 4.8 km of shore. Oceanic processes affect coastal waters much more greatly than estuaries, with various oceanic phenomena. Open ocean: waters overlying the outer continental shelf, continental slope and beyond constitute of the open ocean. Open ocean systems have considerable capacity to dilute, transport, and disperse wastes and associated pollutants due to their large volume and free exchange of water and, hence, are less vulnerable to the impact of waste disposal than other marine waters. Many organisms inhabiting the open sea spend part of their lives in coastal waters and estuaries, where they are subjected to great concentrations of contamination. According to Group of Expert on the Scientific Aspect of Marine pollution (GESAMP) marine pollution is defined as the “introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities including fishing, impairment of quality for use of seawater and reduction of amenities.” 1 Distinction is made between pollution and contamination in marine environments. Pollution occurs when the concentration of a waste substance exceeds the level at which damaging effects are manifested in the sea. In contrast, contamination takes place when the concentration of a waste substance in seawater, sediments, or organisms exceeds background levels without causing measurable damaging effects. Pollutants enter estuarine and coastal marine waters by numerous routes. (1) Untreated or poorly treated sewage discharged. (2) Release large numbers of pathogenic microorganisms that can significantly degrade water quality and pose a serious health hazard to man. (3) Accumulating of toxic substance derived from industrial and municipal wastes, dredged-spoils, and nonpoint source pollution. (4) Physical, chemical, and biological processes affect the distribution and fate of these substances in the marine environment. (5) Various chemical processes – particularly adsorption, desorption, dissolution, oxidation, reduction, flocculation, volatilization, neutralization, and precipitation - influence the availability, persistence, and degradation of wastes in sediments and overlying waters. 2 The deterioration of estuarine and coastal marine waters by waste inputs is often severe and accompanied by a number of over effect such as: 1. Degraded water quality manifested by hypoxia or anoxia over extensive area; 2. Disease, abnormalities, reproductive failure, and mortality of fish and shellfish population; 3. Changes in abundance, diversity, and distribution of marine communities; 4. Loss of submerged aquatic vegetation, wetlands, and other critical habitats; 5. Closure of shellfish grounds and beaches due to chemical or microbial contamination; 6. Outbreaks of human disease caused by individuals swimming in contaminated marine waters or consuming contaminated shellfish. Deep-sea bed has been used for disposal of dredged spoils, sewage sludge, industrial wastes, pharmaceuticals, and low level radioactive wastes. International treaties have been enacted to control the disposal of such wastes. Two of the most important are the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter of 1972 (better known as the London Dumping Convention and now simply the London Convention. 3 The disposal of wastes into the deep sea effectively isolates pollutants from surface living communities in the open ocean and precludes their impact on coastal environments. Studies have revealed increased density of some benthic populations at the dumpsite, owing to increased concentrations of organic carbon which serves as an additional food source. However, the species diversity of the benthic community has declined in response to the sludge dumping. The NEADS dumpsite, which has been in existence since 1967. It lies at a mean depth of 440 m. This dumpsite received large quantities (-2000 mt/yr) of low level radioactive wastes from nuclear power stations. There is little evidence of radioactive impacts on the benthic fauna at NEADS. Although contents of radioactive waste dumped at NEADS are expected to corrode and leach through their containment sometime in the future, the delay should allow enough time to ensure the loss of radioactivity via decay of shorter-lived radionuclide. Pollutants in marine environments derive from both point and nonpoint sources (Table 3). Primary point-source categories responsible for the introduction of pollutants to U.S. marine waters. Major contaminant loadings of 4 U.S. marine waters from point sources have decreased substantially during the past two decades due to tighter state and federal government regulations and improved industrial controls of pointsource discharges. However, the input of non-point-source pollutants is more problematical, and acute and insidious biological effects of these pollutants are extremely difficult to assess.21 Nonpoint runoff is a major source of pollutants to rivers. Nonpoint-source pollutants also originate from this activities at sea associated with accidental release. It is quantitatively significant, particularly on developed coastlines. Nonpoint pollution occurs in virtually all estuarine and coastal marine waters along developed shorelines, varying dramatically both spatially and temporally. Because nonpoint runoff is so diffuse, wide spread, and variable, it is difficult to accurately quantify. Lack of information-gathering, inadequate systematic analyses of gathered data, and ineffective dissemination of results. Marine waste disposal activities continue to be overwhelmingly concentrated in estuarine and coastal marine waters, which receive 80-90% of all wastes released to marine environments worldwide. Outfall discharges and runoff generally deliver greater concentrations of pollutants to these coastal systems than dumping. 5 Because of the great variability in composition of marine-dumped wastes and the intermittent and localized nature of dumping operations, it is difficult to compare pollutant inputs derived from sewage sludge and dredged material dumping and those resulting from pipeline discharges and runoff. Some general observations are possible (Table 4). Nonpoint runoff is the major contributor of fecal coli form bacteria to U.S. marine waters. It also represents the principal source of suspended solids, total phosphorus, and certain heavy metals. The types of pollutants found either locally or regionally depends on several important factors, theses factors are: (1) The relative contributions of agricultural and urban runoff, (2) The type and magnitude of industrial discharges, (3) The size and number of sewage treatment plants that release effluent, (4) The amount of harbor or port maintenance, (5) Affects the input of pollutants and their subsequent biotic impacts on both local and regional scales. 6